1. Field of the Invention
The present invention relates to a magnetic field generating apparatus for use in an undulator as an insertion light source adapted to generate radiation.
2. Description of Prior Art
An undulator according to a prior art which has been used for generating radiation of high brilliance is adapted to generate radiation by causing electrons to travel in a zigzag manner in a periodic magnetic field provided by arranging magnets periodically.
According to the method as mentioned above, it is not possible in principle to avoid generation of integer-order-harmonic waves. In general, in applications of undulators radiation from the undulator is used in combination with a monochromator in order to utilize monochromatic radiation having high brilliance. However, according to the method, harmonic light cannot be removed. Intrusion of such harmonic light is quite detrimental to studies with the use of the radiation. Thus, development of a method to effectively remove such harmonic light has been desired.